Sans' Secret and the Timeline Battle- an Undertale Fanfiction
by thederpypikachu98
Summary: WARNING: VERY SPECIAL SPOILER ALERT! What happens after a Pacifist run when Flowey accidentally scares a human girl into falling down? What will happen when Flowey begins to regain his emotions and Sans reveals his story? Will Frisk RESET? Will Asriel regain his true form? How about Sans' return to his old home? Gender-nuetral Frisk Chara. DISCONTINUED!
1. Chapter 1

**Author's Note~ This is an Undertale fan fiction. Undertale is an amazing game and so I am putting a very special spoiler alert here. Undertale is a game best played while having the least amount of knowledge about it in my opinion, so you get the best gaming experience.**

 **Disclaimer: I do not own Undertale or any characters.**

 **I also am including a couple theories I found on YouTube. I am using one of GameTheory's Undertale theory, so please watch his video if you are confused. I will update this if I use any other theories. I do not own MatPat's theory or any of the games mentioned in his theory. I won't say them now as to not spoil the fic.**

 **This is my first fan fiction that I have published. Any polite criticism is appreciated, and always welcomed.**

 **NOTE: In this Fan Fiction, both Frisk and Chara use they/them terms. I know some people portray them as female, or male, or one or the other, but I decided to write them as gender-neutral. I apologize if you don't like that, and also please let me know immediately if I make a mistake.**

 **This is post-Pacifist run, and begins a week after the barrier is opened. Also, Asgore and Toriel have gotten back together. I'm not good at the whole posting thing, so I don't know how to change the rating.** ** _RATED T TO BE SAFE!_**

The girl stared up at the looming mountain in front of her. It was the mountain that everyone spoke of; terrifying and full of dangerous creatures that would sooner slay you then look at you.

Hours later, as she looked at the deep hole that tunneled straight down, she swallowed and turned to leave.

And stopped as a small yellow flower peered up at her with a curious expression on its face.

She opened her mouth but no sound came out.

It had a mouth and a face and it blinked at her.

"I thought humans were done coming to Mount Ebott," it said.

She really did scream, and stumbled back in shock.

Except there was no ground, and there was only air. She screamed as she fell, and the flower lunged, huge vines bursting out of the ground to try and catch the girl, but it was too late.

Flowey stared at the hole and swallowed.

"Frisk is gonna kill me."

_time_skip_

Frisk rummaged around in the drawer, pulling out all sorts of random items and placing the stuff on the counter nearby.

"You know, Frisk, you didn't have to help me pack up," Toriel said from behind them.

Frisk looked up at the queen. "It's perfectly fine, I enjoy helping everyone."

Toriel smiled and nodded to the kitchen around them. "All that's left are the boxes and then we can carry those to the surface. Or we can eat some butterscotch pie first:"

Frisk agreed and taped the last box shut. Then they sat down as Toriel brought two slices of pie from the fridge.

Frisk was half done when there was a knock at the door.

Toriel went to answer it and Frisk heard a shriek and a whomph as one of her attacks ignited.

"WAIT!" A familiar voice cried out. "I have something to tell you and Frisk!"

Frisk abandoned their pie and bolted for the door to see Asriel- no, Flowey there, looking up at them, one of his petals slightly singed as he had clearly just dodged one of Toriel's attacks.

"As- I mean, Flowey? What's wrong?!" Frisk asked. Toriel gave them a funny look as to why they were greeting Flowey kindly, but they ignored it.

Flowey looked down. "I was up at Mount Ebott and I was looking at the trail and trying to think of a way to block it so no more humans would come through and fall, and then..." Flowey swallowed. "There was a human girl... and I asked her why she was there and she turned to leave the cave and she... she..."

Toriel ignited a fireball in her hand. "YOU CAUSED HER TO FALL?!"

Flowey cringed, obviously scared of his mother, even though she didn't know that he was Asriel. "N-no! I don't-"

Frisk gasped. "She was already looking, wasn't she? I came to see if the rumors were true, and when I fell, I wasn't trying to. There was a rock or something and I tripped...!"

Flowey nodded, still cautious of Toriel. "I tried to catch her but she was already gone, I really did try!"

Toriel made for the door.

"Toriel, maybe its better if As-Flowey and I go find her, she might not be as scared of me as she is of your attacks," Frisk quickly said. "I'll be right back, promise."

Toriel sighed. "Fine. But don't dawdle, and make sure you don't get lost." She glared at Flowey, who looked sad and terrified at the same time.

"Don't worry, I'll be safe with As-Flowey." Frisk began walking and Flowey actually followed, moving along like he was hovering above the ground but still on the ground.

After they were out of earshot, Frisk glanced at Flowey, who moved alone silently, staring at the ground.

"Is it okay if I call you Asriel?" They asked.

"Y-yeah, I'm just not completely used to it yet," Adriel replied. The monster trapped in a flower looked up at Frisk. "Why are you still nice to me? I understand you forgave me and everything, but... I still don't feel anything, I don't have a soul, I-"

Frisk blinked. "Are you hearing what you're saying? 'I don't feel anything?' You obviously do, you looked scared when your mom had that attack ready, and sad when she looked like she didn't trust you, and sounded genuinely concerned about the girl. What if you really DO have feelings?"

Asriel stopped and stared at Frisk. "What?"

Frisk grinned. "See? You're shocked now. Asriel, your feelings are coming back!"

Asriel had tiny tears gathering in his eyes. "I can feel!" He cried, and began laughing. "I haven't felt anything in so long, only a little bit when I... well, when you-know-what happened, and it's just so strange!"

Frisk knelt and wrapped their arms around the tiny flower, careful not to squish his petals. "You can feel!" they grinned.

Asriel smiled. "Thanks, Frisk. Now let's go save that human!"

They rushed through the Ruins to the second room with a patch of golden flowers like Asriel in the center. They avoided it and moved to the first room.

Frisk looked around and saw the bed of golden flowers cradling a small form. Asriel crept closer, carefully moving among the other normal golden flowers. He was only discernible when he moved or glanced back at Frisk.

Then a small green tendril, almost like a vine, sprouted out of the ground right where Adriel's stem entered the ground. It gently tapped the fallen child's arm, who twitched but stayed unconscious.

Frisk shrugged as Asriel once again turned to face theme. "We might have to bring her back to Toriel," they whispered.

Asriel nodded, and seemed to consider his options. Finally, the smaller tendril sank back into the ground and two much larger ones appeared to carefully lift the girl. Frisk stayed behind him as Asriel began going back through the Ruins, being extremely cautious while carrying the girl.

They reached Toriel's home and Asriel hesitated outside the door. "It feels... strange, just going in without permission. I mean, I know it's technically... my mom's house, but it still doesn't feel right."

Frisk nodded. "I'll ask if you can come in."

They ducked into the house and found Toriel already by the exit to the Ruins, waiting. "As-Flowey would like to know if he can come in. The girl was unconscious and he's carrying her, but he said it doesn't feel right if he walks in without permission."

Toriel blinked. "R-really?"

Frisk nodded. "If he can't, that's fine, he can meet us by the barrier."

Toriel shook her head. "N-no! Flowey can come in. And tell him that it was very kind of him to ask."

Frisk returned to Asriel and delivered his mom's message. They led Asriel through the house, who looked around at his former home in sadness and guilt.

Toriel gasped at the sight of the unconscious child that Asriel was carrying. "Oh, my!" She carefully lifted the child into her own arms, and Asriel withdrew the two tendrils. "Thank you, Flowey, for carrying her."

Asriel smiled, a genuine smile, at Toriel. "It's perfectly fine," he whispered.

Toriel led them through the exit to the Ruins, and they traveled through the Underground. Soon they reached the barrier and Asriel flinched as they passed through, and Frisk remembered the events of that day.

Toriel beamed as they exited the Underground and felt the sunlight on their faces. Asriel seemed excited.

It was only about a week since Asriel had opened the barrier, and the monsters all stayed camped out by the place where the barrier had been.

Asriel immediately hid behind Frisk's legs as they came into view of the monster's camp.

Sans, one of the two skeleton brothers, looked up and spotted Asriel, tucked behind Frisk. His white pupils in his eye sockets disappeared and his left eye closed blue and yellow as he stared at the monster-turned-flower. Then he stared at Frisk, who shook their head slightly, and Sans let his eyes return to normal.

"Ah, Tori and Frisk, you-" Asgore saw the human and his expression darkened. "What-"

"I think Flowey here can explain," Toriel said to the group of monsters.

Frisk stepped to the side, and revealed Asriel, who let out a tiny squeak of fear and tried to move back behind Frisk. They gently pushed him back into the open, feeling Asriel shaking as the monsters saw him.

"As-Flowey, don't worry, they won't hurt you, I won't let them," Frisk whispered.

Asriel nodded, still scared stiff, and told the group how he was trying to get a better look at the trail that leads up to Mt. Ebott, and was trying to figure out a good way to block the path. Then he explained how he saw the girl and how he had said he thought humans were done coming to Mt. Ebott, and how "I think I scared her." Asriel looked up at Asgore. "I really didn't mean to, I just wanted to ask her why she was there. She got scared and stepped back but she was already at the hole and then..." he closed his eyes tight. "She fell and I tried to catch her, I really did!"

Undyne snorted. "How? You're a tiny flower with no arms!"

Two of Asriel's tendrils poked out of the ground. Alphys, having been extremely scared and nervous the entire time, suddenly became curious. "Have you always been able to do that?" She asked.

Asriel let them disappear. "N-no, I just realized I could this past week."

Asgore was eyeing Asriel. "How do we know we can trust you?"

Frisk stepped in front of Asriel. "You can trust him. He's regaining some of his old traits, and he can feel again."

Toriel looked up at the setting sun. "Well, we'd all better get some sleep. Tomorrow, this girl and Frisk can bring us to a human village."

 **Author's End Note-** Thanks for chapter 1! I have a few more chapter written already, but I don't know when I'll definitely be able to post. I'm pretty busy but can try to post at least once a week!

Have a sans-sational day!


	2. Chapter 2

**A/N: Chapter 2 is here! I have a few chapters pre-written so it's not like I'm just writing them quickly so I have something to post. I'm not busy at all for this week so I'm probably going to be posting and updating my fics a lot more then I will in the future.**

 **NOTE: Frisk and Chara use they/them/their pronouns. If you don't like it then go ahead and either deal with it or leave. (But read first to see if you like it!)**

 **DISCLAIMER: I DO NOT OWN ANY PART OF UNDERTALE OR ITS CHARACTERS! TOBY FOX OWNS THE AMAZING GAME KNOWN AS UNDERTALE! I ALSO DO NOT OWN EARTHBOUND OR ANY CHARACTERS IN THE MOTHER FRANCHISE! I DO NOT OWN GAMETHEORY'S UNDERTALE THEORY! I only own my OC's and the plotline.**

 **Enjoy!**

In the middle of the night, something shook Frisk awake. They sat up, groggy, to see Sans crouching next to them. "Sans? Is something wrong?"

The skeleton dragged them past the sleeping monsters, and into the darkness of the exit to the Underground. There was a small shape waiting. Frisk's eyes adjusted and Asriel was peering at them from just inside of where the barrier had been. Sans stopped and gestured back towards the sleeping monsters out under the night sky. "Your parents don't know about you, do they." It wasn't a question.

Asriel looked up, terrified. "H-how did you know-"

Sans glared at Frisk. "You haven't reset, either."

"I'm not going to," they said.

The skeleton's eye flared blue and gold. "How are we supposed to trust that? Every other time we get an ending, wether you stay pacifist, or neutral or go genocide, you ALWAYS reset. Why not this time?"

The Reset and Continue buttons appeared in front of Frisk. They took a deep breath.

They moved a hand over the reset button. Sans groaned and began walking away.

And whipped back around when he heard a shattering noise.

Frisk had slammed their fist down on the button, driving their clenched hand right through it and shattering the button. The shattered remains blinked out. "I'm never resetting again," they said firmly, pressing Continue. "I'm tired of resetting, knowing what's going to happen before it actually does."

Sans' eye returned to normal. "Thanks, kid." Then he glared at Asriel. "You've gotta tell them soon."

Asriel shrank back. "I'm n-not ready yet."

"Promise to do it soon, though?" Frisk asked.

Asriel nodded. "Promise."

Chuckling, Sans glanced back to the huge group of sleeping monsters. "Welp, I'd better get back to my position." At Adriel's annoyed look and Frisk's confused face, he explained, "y'know, I actually do keep watch when I need to. Who knows if any humans will wander over and attack?" He shoved his skeletal hands into his pockets and in a blink was gone, already across on the other side of camp.

Asriel sighed. "I'm going to stay here for the night. Some monsters don't like me very much... honestly I don't blame them."

Frisk pulled the monster-turned-flower into a hug. "Don't worry, Asriel. I'll be right here to help or listen if you need someone to talk to! And Sans too, even if he doesn't seem like it."

Asriel smiled. "Thanks, Frisk. Now go get some rest! You're taking us to the human village so you better be awake or I'll eat your breakfast!"

Frisk jogged off, giggling as they clambered back into their sleeping bag. "Goodnight Sans. Goodnight, Asriel," they whispered to the night sky.

"G'night kid," Sans replied softly from his position.

_time_skip_

The reds and golden of the sunrise woke Frisk. They yawned and crawled out of their sleeping bag.

"My child, are you ready to leave?" Toriel asked from a few feet away. She handed the human child some sort of breakfast, they weren't exactly sure what it was. "Asgore decided we would only take a small group as to not alarm the humans."

Frisk wolfed down the strange breakfast item and ran after Toriel. The queen of monsters had gathered six other monsters beside herself to travel to the human village; Asgore, Sans, Papyrus, Undyne, Alphys and surprisingly, Asriel. The human girl that had fallen was cradled in Asgore's arms, any injuries she had obtained during the fall were carefully bandaged.

Papyrus was beaming, hyped to be going to a human village. "HELLO HUMAN FRISK! ARE YOU READY TO LEAD US TO THE HUMAN VILLAGE?!"

Frisk struggled not to laugh at the younger of the two skeleton brothers' excitements. "Erm, yeah, Papyrus. If everyone's here, that is."

Sans began walking towards the very faint trail that snaked through the grass, one that Frisk only knew was there because they had used that very path only a month earlier to climb Mt. Ebott. The group walked and walked, talking and laughing and gasping in wonder at the surface around them. Only Frisk and, shockingly, Sans, stayed relatively quiet and didn't run around asking what every little thing was like a two-year old. A.K.A. Papyrus.

"WHAT'S THIS?!" He cried, holding a caterpillar. "WHAT ABOUT THIS?!" as he poked a snakeskin. "WHAT ARE THE FLUFFY THINGS UP THERE?!" he yelled, shielding his face with his gloved hands as he gazed at the clouds.

Each time, Frisk snorted and shook their head.

Sans patiently answered. "That's a caterpillar. And a snakeskin. And those are clouds."

"WHAT DOES THOSE THINGS MEAN?!"

"A caterpillar is an insect that uses metamorphosis to become a butterfly. A snakeskin is from a snake that molts and sheds its skin. And clouds are... welp, to put it simply, they are what rain and snow and hail and lighting and thunder comes from." Sans calmly explained each item of objects Papyrus asked about, earning quite a few odd looks from Frisk.

A whisp of smoke drifted above the forest they had entered not too long ago. "This way!" Frisk declares, running ahead. There was the human village they had been born in up ahead through the trees.

They hit behind some trees nearby the village. Frisk put a finger to their lips. "I'll see if I can get them to let you come in. Stay hidden!"

Quickly, Frisk managed to get into the village and went to the main square.

"HALT!" A guard roared, spotting Frisk. "WHO ARE YOU, INTRUDER?!"

Frisk swallowed. "My name is Frisk."

The guard froze. "Frisk? But... you can't be Frisk. Frisk climbed Mt. Ebott a month ago."

"I did, and I came back; I have friends you have to meet!" Frisk told the guard. "You can't attack them though!"

The guard finally sighed. "Fine! If you truly are Frisk, then maybe you know what happened to Tina."

Frisk ran and fetched the seven waiting monsters and returned. People began screaming and drawing knives, and some even allowed their souls to manifest as if they were going to attack.

"Tina!"

A woman, with a purple soul, ran towards Asgore. A guard tried to hold her back, but she shoved him away and allowed her soul to return to her body. "Oh, Tina!" She lifted the fallen girl, Tina, into her arms and looked up at Asgore with tears in her eyes. "Oh, thank you so much! Thank you for saving her!"

The first guard suddenly called, "sheath your weapons! Recall your souls! These monsters are friends of Frisk and friends of us!" He stepped forward and dipped his head. "I am Luz. We thank you for bringing our Tina home safely."

Asgore grinned. "We do have some more of our group outside your village. We didn't want to overwhelm you with a large group."

Luz laughed, and led Asgore further into the village. The humans began chatting with the monsters, though Sans, Frisk and Asriel stayed further away.

"You've gotta tell them soon," Sans said to Asriel.

Asriel sighed, letting out his breath in a huff. "I don't know how! Just, 'hey, Mom, Dad, remember me? Your supposedly dead son? Well, I'm the one that you chased away from the newly fallen humans and became a GOD because I stole the human souls and tried to kill everyone?!' Yeah, I'm sure that'll go over well!" Sarcasm dripped from his words, and tears gathered in his eyes.

"I'm sorry, Asriel." Frisk hugged the flower, who swallowed back his tears.

"Sorry for snapping. I just... don't know, okay?" Asriel said after a moment.

Sans shrugged. "It seems like there hasn't been any major problems that have... a-rose," his eyes shining with laughter.

Asriel turned and went back towards the main group. "That's it. I'm out."

Frisk swatted at Sans. "You know he doesn't like puns! Especially not flower puns!"

"Couldn't help myself."

 **End A/N:**

 **Derpy: I have so many puns lined up to use. *chuckles***

 **Sans: *high fives Derpy***

 **Asriel: *in the distance ... slamming his head against a wall.* OH MY FUCKING GOD WHYYYY?!**

 **Sans: What? Are my puns a thorn in your side?**

 **Derpy: C'mon Sans, let's not make him mad again.**

 **Derpy: But really, Asriel, do I need to back-petal to the beginning and write more puns or would you rather keep them in the A/N?**

 **Asriel: I SWEAR I'M GONNA KILL YOU IF YOU MAKE ONE MORE PUN**

 **Sans: Why? You deserve some pun-ishment!**

 **Asriel: *Flips table* *throws chairs* *throws computer* *throws Derpy and Sans out the window* SHUT THE FUCK UP SANS!**

 **Papyrus: YES SMOL FLOWER PLEASE MAKE SURE HE DOESN'T MAKE ANYMORE PUNS! BUT BE CAREFUL! MY BROTHER HAS ONLY 1 HP!**

 **Asriel:...**

 **Asriel: Don't call me 'smol flower.'**

 **Papyrus: WHAT?**

 **Asriel: *pun-ts Papyrus out the window***

 **Derpy: HA**

 **Sans: YOU LITTLE- *teleports in front of Asriel while standing on a huge Gaster Blaster.* DON'T *blast* TOUCH *blast* MY *blast* BROTHER! *blast***

 **Derpy: Alright, chill! We can't go killing characters when this is only a small A/N thingy... what even is this anymore?!**

 **Asriel: *books it* CRAP I PISSED SMILEY TRASHBAG OFF!**

 **Sans: *Chases him with a dozen Gaster Blasters firing* WHAT DID YOU CALL ME?! YOU GOAT-PLANT GARBAGE! *both run out of earshot.***

 **Papyrus: *returns from his trip out the window* BYE HUMANS!**

 **Derpy: *shoves Papyrus after Sans* okay I got carried away but oh well there's more puns and I'm talking fast so I can go save Asriel from Sans's wrath 'kay bye!**

 **Actual note: Frisk and Tina's village is the descendants of magic users and in order to keep their souls strong, avoid modern things and most technology. Just wants to explain!**


	3. Chapter 3

**A/N: Chapter 3 is here! WITH EXTREME SPOILERS FOR UNDERTALE! READ WITH CAUTION IF YOU HAVEN'T PLAYED THE GAME!**

 **I am so hyped and can't wait for the really insane parts of this story! I wish I could post it all at once, but I only have about half written and don't want to overwhelm anyone with a large amount to read.**

 **Thanks to Shiny Victini 4 for reviewing! I'm glad you like this fic. And I chose to have Frisk and Chara use they/them/their pronouns because in Undertale, monsters refer to Frisk and Chara with they/them/their pronouns. I know that might be because the monsters are polite enough not to ask, seeing as they only asked Frisk's name at the very END of the game, but I prefer them as using they/them/their pronouns. It really made me happy to see that I can make content that people like to read!**

 **DISCLAIMER: I DO NOT OWN UNDERTALE OR ANY CHARACTERS! I DO NOT OWN EARTHBOUND OR ANY CHARACTERS! I DO NOT OWN GAMETHEORY'S UNDERTALE THEORY! I only own my OC's and the plotline.**

 **NOTE: Frisk and Chara use they/them/their pronouns, as stated above. If you don't like that, either deal with it or leave. (AFTER READING OR REVIEWING FIRST PLEASE!)**

 **NOTE 2: Monster Kid is a female in my story, and uses she/her pronouns. Just letting you know!**

 **NOTE 3: (wow, what's next, note five million?) Frisk and Asriel, (and by default Chara), are in about fifth grade, making them anywhere from 9 to 11. I won't put a specific age because I know some people like them older while others like them still as children and I agree with both.**

 **Enjoy!**

Frisk cheerfully skipped inside the house, having just come back from hanging out with Monster Kid. Toriel was pouring over a cookbook in the kitchen, muttering as she added pinches of ingredients to a pot on the stove. Sans and Asriel sat at the table, Asriel stuck in a pot of dirt. "Hey, kid," Sans said.

"Hi Sans, hi As-Flowey, when'd you get here?" Frisk sat down next to Asriel at the table.

Asriel looked at Toriel, who was clearly occupied with her cooking. "M-Toriel invited us over to try out her new recipe. It smells really good." This last comment was projected much louder, so that Toriel could hear.

"Thank you, Flowey! I just don't know why it's not cooking right..." Toriel frowned.

Frisk got up and looked at the cookbook. "You've gotta put it in the oven, not on the stovetop. That's why it's not cooking fully." They flipped on the oven and helped Toriel put the pot in the oven. "Now we set the timer and wait!"

Toriel sighed. "Thank goodness! I thought I was doing something wrong, but it just needed to go in the oven."

They all sat down and Toriel brought out some tea. "Asgore's at the press conference out of town," she told Frisk.

Frisk nodded.

Asriel suddenly took a deep breath. "I need to tell you something, m-Toriel."

Frisk jerked their head around to stare at Asriel. "A-Flowey! Are you completely sure you're ready?!"

Sans nodded. "You may never be able to get back to your original body."

Asriel growled. "I know that! But this way, we can see if Alphys can help me!"

Toriel looked concerned. "Flowey? Is there something wrong?"

Asriel suddenly burst out, "momitsmeAsrielI'maflowerandIdon'tknowhowtobecomemyselfagain!"

Toriel blinked. "What?"

"I'm sorry for taking Chara's body to the human village," Asriel whispered. "I'm sorry I didn't come back..."

Toriel stared at Asriel. Then tears formed in her eyes. "A-Asriel?!"

Tears began pouring down his face. "H-hey, Mom."

Toriel threw her arms around the monster-turned-flower, sobbing. "Oh, Asriel!"

Sans stood and beckoned Frisk out so Toriel and her son could have a moment to talk. He led Frisk out to the living room and they sat on the couch.

"How are we going to change him back?" Frisk finally asked.

Sans glanced at them. "All he needs is a soul." At Frisk's confused look, Sans chuckled and leaned back against the couch, hands behind his head. "You two had explained that before he had opened the barrier, Asriel had all of our souls and the six human ones. He was himself, he had a soul to anchor his being as a monster. But he gave up all the souls, and he didn't have any anymore. The DETERMINATION that he had gathered from the souls sustained him until after you went back to see him before we left the Underground. After the DETERMINATION was gone... he became a flower again. But there's something I think is weird."

"What?" Frisk had never thought of returning Asriel to his monster form to be this easy before.

"He doesn't need a soul. He's got six already."

Frisk's jaw dropped.

"Listen. We never found the six human souls after the barrier was broken. We assume they were destroyed, but Asriel's been giving off this feeling that there was a sense of power in him, and I didn't know what it was until now. He still has the six human souls, but he doesn't know he does. If he could manage to harness the human souls, he could become himself again. He would have plenty of the traits to keep him as a monster, and once he has a soul he can get his own DETERMINATION."

Frisk nodded slowly. "Yeah... that could work!"

_time_skip_

Asriel shivered, staring at the building that he could see plainly down the road.

"You okay, Asriel?" Sans asked.

Asriel nodded from his flowerpot that was clutched in Frisk's arms. "Yeah, I think I'm just nervous."

Frisk smiled as they walked next to Sans. "It's okay! Since Toriel's a teacher at the S.O.U.L. School, Sans can walk us to school! He's even coming to the PTA meetings!"

"Anyways, it's not like this is actually the first day," Sans said as they paused at a stopsign, then continued. "It's just a few hours where the kids get to know one another, and the parents or guardians meet with the teacher. Nothin' to be afraid of!"

Asriel smiled unconvincingly. "Yeah..."

Sans managed to get them all into the building and to the right class within a few minutes of the four-hour school introduction day beginning.

Sans spotted the teacher, a red-haired woman with a nametag reading, 'Miss Jaipa.' She was smiling at a parent who had walked in just before Sans and Frisk.

After Miss Jaipa was done, Sans cleared his nonexistent throat. "Hello, Miss Jaipa. My name is Sans and this is Frisk, and Asriel."

Miss Jaipa's face went from cheerful to barely hidden disgust in the span of three-point-two seconds. She frowned. "Oh. You're Mrs. Dreemurr's children?"

Frisk swallowed. "Um, yes. Hi, I'm Frisk."

"But you're human and Mrs. Dreemurr is-" Miss Jaipa coughed. "Sorry. Your seats are over there by the window. Your nametags should be on your desk."

Sans followed Frisk and Asriel over to their desks, the two closest to the window. And farthest from Miss Jaipa, he realized. He picked up Asriel's name tag. "Asriel Dreemurr," he read.

Asriel groaned. "If those are the sticker ones, just tape it to my flowerpot. I hate it when you peel stickers off and that gooey stuff is left behind."

Frisk and Sans exchanged a knowing look before Frisk went to find the tape, returning quickly. Sans taped Asriel's name tag to his flowerpot while Frisk peeled theirs off and stuck it to their sweater.

Miss Jaipa rang a small bell that sat in her desk at the front of the room. "Hello, parents and students! My name is Miss Jaipa. Students, you are free to chat and move around on that side of the room while the parents and I have a small PTA meeting."

Parents began moving towards Miss Jaipa. Sans winked at Frisk and Asriel, and joined them. The students suddenly crowded around Frisk and Asriel.

"Is it true that you two are Principal Dreemurr's kids?" One kid asked.

"That can't be right!" Another child retorted. "Frick here is human while Planty here is a freaking sunflower."

Asriel shoved his anger down inside of him. "For your information, I don't usually look like this. I'm different. This is just... temporary."

"And there's such things as adoptions," Frisk replied. "My name is Frisk, not Frick."

The first child snorted. "Well, she's a monster, not a human."

Frisk shrugged. "That's why she's not my mom." They winced slightly as Asriel seemed to droop, then continued. "She's my **mom** -ster!"

A few other students began laughing as Asriel brightened, giggling slightly. Frisk grinned. "Anyone want to hear about the Underground?"

At least six kids cried out, "yeah!"

Frisk and Asriel grinned. "Deep under Mount Ebott lay the Underground, a place where monsters lived peacefully for many years..." Frisk began.

_time_skip_

Sans was listening to Frisk and Asriel recount their time at the school as they walked back towards Toriel and Asgore's home. They passed a construction site that was busy building some sort of skyscraper.

Sans felt a shiver run down his spine and he glanced up to where the men and women were working on the frame of the building. One of the cranes creaked and his eye sockets widened.

The workers cried out as the crane seemed to shake, then snapped, and the huge load of beams plummeted. Sans shoved Frisk behind him and thrust his hands up, his left eye blazing with magic. A blue glow surrounded both his hands and the beams, and the beams froze, hovering in mid-air. Straining, Sans focused on keeping the beams from hitting the skyscraper or any workers.

Frisk squeezed their eyes shut, pulling Adriel's flowerpot closer to protect him. Asriel cried out and Sans yelled, "RUN!"

Then there was a distinct humming noise and Frisk flinched away from the coming impact.

But the impact never happened. Something shifted in Frisk's arms, and they cautiously opened their eyes. The beam that slipped from Sans' control was frozen above the ground, shrouded in green magic, shield magic.

And then they realized that Asriel was staring up at the beam with DETERMINATON in his green... his...

Asriel's green eyes shone in his flower face, where before they had been black irises. Then, as Frisk watched, Asriel slowly grew larger, spiraling upwards until he had white fur, a green and yellow sweater and green magic sparking in his paw-hands.

 **Ending A/N:**

 **And next time Sans will tell Frisk and Asriel his story.**

 **I really hope everyone liked this chapter. I don't like time skips, but I use them when it's more than a few hours or a night passing.**

 **Please review and tell me what you think and if I make any mistakes please let me know so I can improve my fic for everyone!**

 **Thanks!**

 **P.S. I absolutely had to have Sans in the PTA. And also the 'mom-ster' joke. It was a neccesity.**


	4. Chapter 4

**A/N: Chapter 4!**

 **Sans will be spilling his secrets out today and possibly the return of some characters. Also go get yourself a bowl and a spoon and some milk because here come the feel-ios!**

 **ShinyVictini4 - I have even more planned for Asriel for the future! I didn't realize that people didn't like the Sans=Ness theory as much as others until I started writing this, and I'm glad someone does. Thank you so much for reviewing!**

 **DISCLAIMER: I DO NOT OWN UNDERTALE OR ANY CHARACTERS! I DO NOT OWN EARTHBOUND OR ANY OF THE MOTHER SERIES OR CHARACTERS! I only own my OC's and the storyline. I DO NOT OWN THE SANS=NESS THEORY!**

 **NOTE: Frisk and Chara are both non-binary and use they/them/their pronouns. Monster Kid is female, Napstablook and Mettaton are both male. Don't like it then leave (AFTER READING OR REVIEWING!)**

 **Enjoy!**

Frisk had helped Asriel walk at first, so he could get used to his legs again. After all, he'd been a flower for how many years now?

They reached their street and Sans blinked. "Toriel must've gotten done with her SOUL school meetings early. She's home."

Asriel's eyes widened.

Sans led them towards Toriel and Asgore's house, and entered before Asriel could protest. "Hey, Toriel?" He called. "There's someone here that you need to see!"

Asriel sucked in a breath and tried to hide behind Frisk.

Toriel hustled out of the kitchen, wiping her paws on her dress. When she spotted her son peeking out from behind Frisk, her paws flew to her mouth in shock. "Asriel?!"

Asriel suddenly ran towards her and hugged her, pressing his face into her dress. She pulled him closer, happy tears leaving tear tracks through her fur. "How-"

Sans shoved his hands into his jacket pocket. "The human souls." After explaining what had happened, he then told Toriel his and Frisk's theory. "If we can activate all the human souls permanently, Asriel's soul should reactivate. Once that happens, his monster form should become his normal one again."

Toriel glanced at the skeleton. "'Reactivate?'"

"A monster cannot live without a soul. Neither can a human, but their bodies persist after death, unlike a monsters'. Asriel still has some sort of soul besides the human souls or else he couldn't exist as Flowey. The reason you lost your ability to feel and have a monster form was because of your soul; it's either fractured or cannot produce your trait," Sans explained. "And if you can't produce your trait, then you can't maintain a monster form. You're VERY lucky that Alphys was able to take the remains of your soul and some of the ash from your monster form and inject it into the flower. Otherwise your soul would have... well, you wouldn't be here."

"Have you told Asgore?" Frisk asked.

The wife and son of King Asgore had their answer plain on their faces.

Sans groaned. "He's one of the only people you should have told right from the start. You know if that if you wait and he finds out by himself, he's not gonna be happy."

"First I want to help Asriel stay as his monster form. Then we'll tell Asgore," Toriel said.

Sans closed his eyes, chuckling. "You're lucky that I know the perfect guy to help you." His left eye opened, glowing blue.

A blue aura surrounded Frisk, Asriel and Toriel. Sans raised his hand and snapped his fingers.

They disappeared, leaving the empty hallway behind.

...

Sans grinned as the other three materialized in front of him. "Arghhhgh!" Frisk moaned. "That feels terrible!" Asriel and Toriel had the same uncomfortable looks on their faces.

"Well, we're gonna have to do it again later," Sans said cheerfully.

Asriel looked around. "Is this... Snowdin?"

Sans chuckled. "Yep." The skeleton began walking through the town, and didn't seem to mind that his slippered feet were ankle-deep in the snow. He led them to his and Papyrus' old house, still lit up brightly. "Now, you can't tell anyone about this, 'kay? You'll be the first to ever know, except for Frisk in other... well, Frisk knows what I mean. Pap doesn't know, and I've had a hard time keeping this from him, so do me a favor and shut your mouths." Sans ducked behind his house and, as Frisk, Asriel and Toriel followed, stopped in front of a hidden door.

His eyesocket lit up and a blue aura surrounded the door, and seconds later it swung open. "Welcome to my lab." Sans was gone, and lights flipped on inside. "You might want to come in, by the way," he called.

Asriel looked around in wonder. "Seems like a very simple lab."

Sans yanked a huge cloth off of a shape at the other side of the room. "That's how I like it." The shape under the cloth was a huge machine, with an open panel.

Frisk stared at it. "What's that?"

Sans chuckled and a massive rolling toolbox shot over from the wall, and his eye lit up as his magic lifted tools into the air. "This is how we're gonna get Asriel to stay as a monster and activate his soul." He grabbed some sort of tool and disappeared under the machine, while the other floating tools began working on various parts of the machine. "I originally tried fixing it to try and get back to... uh, my home, but that didn't work out. So I started modifying it to try and travel to a special place to rescue someone." His voice came from under the machine, and banging accompanied his words. "Every time I get close, everything... well, everything gets reset. And not because of anything I'm doing. It's... something... else." Sans climbed out from under the machine, yanked off his blue jacket and grabbed a different set of tools, diving back under the machine. "But now..."

The machine suddenly roared to life, a screen lighting up in front with seven switches around the screen. Sans yelled, and teleported out, beaming.

"And what does this do?" Toriel asked.

The screen was covered in a strange language, runes that they didn't recognize, but clearly Sans did. His bony hands flew across the screen, rapidly typing and changing things. As he worked he spoke, though he focused on the screen. "We need to get to another timeline. This world is one of thousands, even millions, and we need to get to two of them. Or more accurately, we need to get to one and then an in-between timeline." He stepped back and shrugged his jacket back on. "First I need to tell you something so it's not a shock later.

"I don't know if you knew this but I'm not originally from the Underground. You could say I'm from the surface, but it's a different surface in a different timeline. This machine is what brought me here, but it broke and turned me and Pap into skeletons. I took the remains of the machine and built this thing. It works, but I haven't gone anywhere.

"My name wasn't Sans in my home timeline.

"It was Ness."

...

"I was a human. I had three friends named Paula, Jeff and Poo." He pulled a picture out of one of the drawers, and handed it to them. "We had to go back in time in our machine called the Phase Distorter, and destroy an alien named Gygias. We did, but with a consequence. We created two timelines; our original, and a new one. We returned to our first one and when we got there, the world was warped and changed, and we were forced to run.

"The Phase Distorter was a strange thing though, we couldn't transport organic material in it, so Jeff's father implanted our souls into robots. When we came back to our home timeline I managed to transfer myself to my body again, but my friends couldn't. Their bodies had disappeared. Then the timeline began warping and we had to flee. Monsters such as Starmen and Zombies chased us into the Phase Distorter before we could stop them, and a Starman managed to get in with us.

"And... we used the Phase Distorter."

Sans was crying now, wrapping his arms around himself. He swallowed and continued.

"I didn't know what happened - one minute I was crammed into the Phase Distorter with my friends and a Starman - the next... I was falling, and then nothing.

"I woke up with a skeleton next to me. It wore armor like a Starman's, and then I realized the consequences of putting organic material into the Phase Distorter; you did, but not completely. I becamse a skeleton, and we had come to this timeline, the Undertale Timeline.

"My friends were gone. The remains of the Phase Distorter were scattered around us in the snowy forest. Up ahead I could see a village, so I managed to get there and get the house. It was empty and no one had lived there for years. When I went back to get the Phase Distorter and the Starman, I had no way to get them to the house until my eyesocket began glowing and my magic activated. I don't know if it was my emotions or my soul or the situation or whatever, but it started. I managed to get the Phase Distorter down here and the Starman into the house.

"Snowdin accepted us. The Starman had woken up without any memories and I gave him a name. Papyrus believed, and still does, that he's my brother. I guess we sort of are. Two living things with no way to get back to our home.

"We didn't age very much. Neither did the monsters in Snowdin." Sans finally sighed, rubbing his face to get the tears away. "But I know how to get Asriel help. We need to find someone who can lead us to get help.

"His name was W.D. Gaster. He was a monster who lived here, but after the third reset, he disappeared. No one seemed to remember him... no one else remembered other resets, not even Papyrus.

"And it went on. Until now, when the reset button was shattered and we had this timeline forever."Sans yanked up his hood, the fluffy down casting a shadow over his face. He wiped away the tears and took a deep breath. "We have to get to Gaster in order to find the people who can help you, Asriel."

Asriel looked up at Sans. "Y-you told us your story and your secrets for me?"

Sans rubbed the top of his head affectionately. "Don't worry 'bout it. I needed to tell someone eventually and you guys are my closest friends."

"If this thing is made from the Phase Distorter, won't we...?" Toriel asked worriedly.

Sans waved her off as he pulled an old bag out of one of the drawers. He stuffed the picture, a book and a roll of a blue paper into it, and slung it over his back. A badge with a lighting bolt was attached to it, and it seemed to shine as Sans' hand brushed against it. "No. That part of the Phase Distorter was destroyed. Even if it wasn't, I would probably have destroyed it myself. We're safe."

Frisk reached out and took Sans' hand. We'll be right here, Sans." They smiled at him, and he cheekily grinned back. Or, technically, just grinned because he was a skeleton.

Toriel cried out as a white light enveloped Asriel and when it faded, he was a flower again.

"The DETERMINATION from the green human soul ran out." Sans picked Asriel up in his flowerpot and handed him to Toriel. "Now hold onto my coat and DON'T let go unless you want to get lost between timelines."

Toriel froze as a beeping sound filled the air. Checking her phone, she winced. "Oh no. Asgore's calling me."

Sans hissed. "Alright, change of plans. Forgot he was supposed to be getting back from that conference out of town. Toriel, stay here. Asriel and Frisk, you'll come with me."

Toriel sighed. "Fine."

Sans snorted as she handed Asriel to Frisk. "What, not gonna argue?"

Toriel shook her head. "Nope. You'll just force me to stay." She turned and left the room quickly, pulling her phone out.

Sans pressed a button and the world went dark.

Frisk was floating in the darkness, clutching Sans' coat sleeve and Asriel.

Sans smirked. "Told'ya it'd work." He turned and somehow floated forward, pulling Frisk along.

A shape floated in the distance, a slightly darker black then the darkness around them. Sans grinned. "Heya Gaster."

The shape moved and a white face appeared from beneath the folds of its cloak. "Sans?"

Sans winked. "You betcha."

Gaster looked at Frisk and Asriel. "You brought a human and a flower."

Asriel deflated a small bit.

"Gaster, this is Frisk, and the 'flower' is Prince Asriel Dreemurr. He needs help and you are part of that help," Sans said.

Gaster winced. "My apologies. Asriel, I will help you in exchange for Sans getting me out of this horrid place."

Sans laughed. "We've got that under control. You need to take us to... the Mother Timeline."

Gaster narrowed his eye sockets. "And you're truly okay if it's... that one...?" Sans nodded. "Okay. To the Mother Timeline we go."

Sans snapped his fingers and the machine he had built appeared in the darkness. He and Gaster floated in front of it, Frisk clinging to Sans' sleeve.

Gaster spoke something in a strange language and his eyes flared, his left eye blue and his right orange.

And they disappeared from the dark world.

 **Ending A/N: So how were those feel-ios?**

 **Sorry!**

 **The next chapter will be out tomorrow. The reason it took me so long today was because I was working on my other Undertale fic and had all this crazy stuff to finish first. Also, I hope you guys liked this! I was going to add more, but it's already kind of a long chapter.**

 **Please leave a review so I can improve my fics for you guys!**


	5. Chapter 5

**A/N: ALRIGHT! After three rewrites and edits, and dealing with a broken (now dead) computer, I have managed to get my cousin to allow me to borrow her computer!**

 **The reason I haven't updated, if you haven't checked my profile, was because my computer had issues. And Friday, it was permanantly dead, leaving me with my recent chapters having to be rewritten. For the third time.**

 **So now I'm back with chapter 5! Finally! Thank you guys so much for reviewing and all of you who have followed my fic! I've also decided I'll be posting new chapters on Sunday, so I can work on making longer chapters.**

 **DISCLAIMER: I DO NOT OWN UNDERTALE OR ANY CHARACTERS! I DO NOT OWN EARTHBOUND OR ANY CHARACTERS! I DO NOT OWN THE UNDERTALE/EARTHBOUND THEORY!**

 **NOTE: Frisk and Chara are non-binary. They use they/them/their pronouns. Mettaton is male, and Monster Kid is female. Don't like it? Deal with it or leave (AFTER READING FIRST!)**

 **NOTE 2: I have never played Earthbound before. I'm going off pictures online and MatPat's videos. I also might include his latest theory on Gaster's true identity later on.**

 **NOTE 3: (omg): I have the SOUL traits represent different things; red=determination, blue=integrity, orange=bravery, green=kindness, yellow=courage, purple=perserverance. I also have each trait giving the human/boss monster an extra strength in a certain ability. Also, boss monster's souls are silver inverted hearts, with their trait glowing underneath. Normal monsters are just plain white inverted hearts.**

 **ENJOY!**

A blue sky greeted them. Sans suddenly gasped and fell to his hands and knees.

Gaster sighed. "I'm sorry, Sans. There might be a bit of-"

Sans shook his head. "n-no, it's not that. i'm just... i'm... we're close to my friends, i can feel it."

Asriel looked around. "So does that mean they can feel you?"

Sans stood and looked around. "not the usual place..." he muttered, and began walking in a random direction. Gaster followed, Frisk and Asriel on his heels.

They were on a hill, and in the distance loomed a city ablaze with lights. They walked and walked. Half-way there, Sans jerked his head up. They stood at the crest of a hill, another right in front of them. Three shapes appeared on the hill in front of them.

Sans suddenly started running, the figures sprinting down the hill. He suddenly tripped and teleporting back forward, running.

Frisk bolted after her friend, Asriel yelping as they sprang forward.

Sans crashed into the three shapes, throwing his arms around them. They all stepped back and that was when the three people realized that he was a skeleton.

"Sans! Wait... up...!" Frisk gasped, skidding to a halt beside Sans.

"'Sans?'" The one human asked, looking confused. "Ness, what are they talking about?"

"Did the Phase Distorter turn you into a skeleton? And that Starman?" The girl asked.

Sans chuckled nervously, his hood still up. "erm, yeah, about that... I got sent to the undertale timeline. the starman got turned into a skeleton named papyrus and I had to change my name to 'sans.'"

The last human boy frowned. "But who're they?"

Sans smiled. "this is frisk, w.d. gaster, and asriel dreemurr. frisk, asriel, gaster, this is paula, jeff, and poo."

Paula squinted. "Another skeleton, a flower and a kid?"

Sans shook off his hood. "guys, we need your help." He explained about Adriel's predicament.

"Ness, do you really think we can help?" Poo asked. "We have experience with Earthbound monsters, not... whatever Timeline these guys came from."

Clearing his throat, Sans told them, "it's sans now. and it's your souls that can help."

Jeff pushed up his glasses. "My father is out of town for another week. Let's go, we're wasting daylight."

Snapping his fingers, Sans' eyesocket flashed blue and they disappeared as the machine took them away.

...

Sans was already out the door by the time the rest of them got their bearings. Toriel was introduced and Sans instructed everyone to grab hold of him. Then he teleported out of the lab and to the flat land at the base of Mt. Ebott.

"so we're gonna need a display of each trait to activate asriel's soul," Sans was already pacing out a huge circle. "frisk, set asriel here and get him out of that flowerpot. poo, stand here, then paula, jeff, toriel, gaster and frisk. When i can say go, just breathe and don't move." Sans stood in the circle and his let eyesocket started glowing blue. "go."

Everyone breathed out as one, and Sans' hands glowed blue. Around the circle, a heart shot out of each of the monsters or humans. Sans, silver with blue, a hint of red and another color no one could make out; Poo was yellow; Paula, green; Jeff, purple; Frisk, red; Gaster, white with light blue and orange; and Toriel, silver with red. They hummed and Sans snapped his fingers.

A beam shot out from each of the souls, directed at Asriel. They hit hm and his form wavered.

Seven souls appeared around Asriel; orange, yellow, green, light blue, dark blue and purple; and a dull red soul that was partially shattered.

The six human souls that came from Asriel swirled together and locked into his soul, creating a rainbow hue in the heart. It zoomed back to him and his form expanded. The beams dropped and the souls returned to their owners. Asriel stared at his paws, shocked.

Sans swayed. Gaster teleported next to him and caught him, cradling him on a Gaster Shield. "Sans!" Frisk cried. They rushed over to the Gaster shield, and stared at Sans.

"He's okay. He just needs a lot of rest," Gaster said from beside them. "Sans not only teleported a lot of people around multiple times, but he had to finish the Time Distorter ll, activate that, and when he found me, activate it to get to the Mother Timeline, then activate it again to get all of us back to the Undertale Timeline, and after that, he still teleported us all out here. Then he pulled the souls out of us and got them to activate Asriel's. That was really pushing his limits." Gaster examined Sans. "I'm shocked he didn't pass out sooner."

Jeff, Paula and Poo crowded around Sans. They had extremely concerned looks on their faces.

Toriel's cell phone rang, startling them. She checked it and gulped. "Asgore's calling me again. What does he want?" She quickly walked away from the group to answer, Asriel trailing over to where the rest of the group was.

Gaster sighed. "I'm afraid you three won't be able to return to your timeline until he wakes up. That may be only a few hours, or a few days."

Paula nodded. "That's okay. We can wait."

"Ness always did get exhausted after a while of battling and stuff," Poo added.

"Sans."

Asriel glared at the three friends of Sans. "He said his name is now Sans. Unless you didn't hear him."

Poo crossed his arms. "His name is Ness."

Gaster growled. "Now, now, let's not-"

"It's SANS!"

"NESS!"

"SANS"

"NESS"

"SHUT UP!" Frisk shrieked. Everyone stared at them. "For now, call him Sans, so if you have to come to the city you won't confuse everyone. We can ask him which he prefers when he wakes up."

Gaster dipped his head. "I can teleport us to the city. It will drain a lot of my magic if I have to teleport all of you, so be ready to catch Sans if my shield fails."

They all gathered together and Gaster teleported them away.

...

Almost immediately, when they appeared in Toriel and Asgore's front yard, Gaster collapsed, exhausted, and his Gaster Shield vaporized. A green shield appeared and caught both of the skeletons, and Asriel's jaw dropped as his paw began glowing green.

The front door flew open and slammed against the house as Asgore bolted out, leaping over the porch railing and skidding to a halt as he spotted Asriel.

"As...riel?"

"Hey, Dad," Asriel whispered, and practically threw himself into his father's arms.

 **A/N: So that's a wrap!**

 **Sans will have lowercase normal text, Papyrus will have all caps normal text. Didn't do that in other chapters I think, so it's a change now.**

 **The next update will be next Sunday! Please review and let me know how you liked it!**


	6. Chapter 6

**A/N: Hi!**

 **So if any of you guys read more than just one of my fics and are wondering why I haven't updated my other two, (Pokémon: Vinoa and Undertale Mini Stories thingy) it's bececause a) I haven't gotten another chapter written yet for Undertale Mini Stories, but I** **will** **be changing it to its own story because it's most likely going to be more than just a small fic. Pokémon Vinoa is also in the works, and won't be out for another couple of weeks. b) I'm doing research for both of them. I'm trying to find more about the different AU's for Undertale and a way to put multiple areas and cities on an island/continent thingy for Pokémon.**

 **If you guys want, I can start posting another fic I've had written since the first chapter of the Undertale Mini Stories (I'm going to have to come up with a name for that).**

 **Anyways, back to this fic!**

 **DISCLAIMER: I DO NOT OWN UNDERTALE OR ANY OF ITS CHARACTERS! I DO NOT OWN EARTHBOUND, THE MOTHER SERIES, OR ANY OF ITS CHARACTERS! I DO NOT OWN THE SANS=NESS THEORY! (That belongs to MatPat on GameTheory)**

 **NOTE: Frisk and Chara are non-binary. Mettaton is male. IF YOU DON'T LIKE IT, THEN LEAVE (after reading and/or reviewing first).**

 **NOTE 2: I have not played Earthbound before. I'm going off of YouTube videos and images online.**

 **Enjoy!**

Asgore sighed. "Well, Sans can stay here while he recovers. I'll have to contact Papyrus and let him know."

"Jeff, Paula, Poo, you can have the basement. There's just the perfect amount of air mattresses," Toriel said. "I can help you get them out tonight."

Asgore thought a moment. "Gaster and Sans can rest in the guest bedroom. Asriel, you already know your things from the Underground were brought here."

...

Frisk woke to hear a creak outside their door. Across the room, Asriel sat up in bed. "Did you hear that?" He hissed.

Frisk put a finger to their lips. The doorknob twisted and the door slowly swung open.

A small figure, Frisk's size, entered the room. Their eyes glinted red and there was something clutched in their hand.

The figure crept closer to Frisk's bed. They pretended to be asleep, but readied an attack. Asriel slipped silently out of bed and crept closer.

A knife.

That what the figure held.

Frisk dove out of the way as the figure brought the small blade down. It sliced through the pillow and stuck in the mattress.

"Asriel, run!" Frisk shrieked. They brought a red shield up as their soul responded to the danger and defended them.

Asriel managed to get to the light switch and froze as he caught sight of the mysterious person.

"Chara...?"

Chats whipped around, eyes glowing red with hatred. "Asriel! You always get in the way of EVERYTHING!"

Asriel leaped out into the hallway. Chara lunged after him, and Frisk ran after them.

Asriel yelled as Chara attacked, barely dodging as the blade scratched against the wall. He managed to dive down the stairs and out the front door. He was completely focused on leading Chara away from the less strong monsters and humans in the house.

Frisk slammed the door shut and swallowed as their vision turned black and white. "Asriel..."

Asriel suddenly ducked as Chara launched attacks, raising shields around himself. "Chara! Stop! You don't have to do this!"

Chara hissed, their fury growing. "You didn't get the souls when you took my body to my village. You didn't open the barrier!"

Asriel blocked another attack. "Yes I did! I did!" He winced as a blow barely grazed his fur. "And now the monsters are free!"

Chara roared. "NO! I WAS SUPPOSED TO USE THE HUMAN SOULS, NOT YOU! I WAS SUPPOSED TO BECOME A GOD, NOT YOU!"

And they hit Asriel.

Seconds later, a blue-white beam slammed into Chara. Their health drained to zero, and their soul shattered. A Gaster Blaster disappeared from behind where Chara had been.

"you two okay?" Sans asked. He was panting, still exhausted.

"B-but-" Frisk whispered.

Asriel nodded. "I'm fine. Chara only took a tiny bit of health."

Sans winced. "this is why i hoped i wouldn't get so tired. chara's become more than a human - they're a glitch in the timelines." Then he stumbled, falling forwards.

"Sans!" Asriel caught the exhausted skeleton in a green shield.

Sans grinned weakly. "m'fine, just tired. today really wore me down to the bone." Frisk let out a little giggle, while Asriel rolled his eyes. "what's wrong? you know this is asriel as it gets."

With a soft click, Frisk managed to catch Asriel's shield and turn it red before he dropped it. "I'm done," Asriel said, turning and walking back to the front door. "Hurry up and let's get to bed before anyone else notices we aren't in bed."

A bit of pushing, shoving, and a bottle of ketchup later, Sans was in the guest room, where two twin beds allows for both him and Gaster to recover. Gaster was still asleep.

Sans flopped down on his bed, face-first, and went right to sleep after saying, "'night kids."

"Goodnight, Sans," whispered Frisk. They closed the door behind them and followed Asriel to their room.

Diving under the covers, the monster yawned. "G'night, Frisk."

They climbed into bed. "Goodnight, Asriel."

Moonlight eventually shifted to sunlight, shining through the windows. Gaster and Sans woke up pretty fast, surprisingly.

Asgore was ecstatic to have his old friend back, even going as far as to call Alphys to invite her over for the day. Sans' friends just quietly sat and ate their pancakes.

Around nine, Frisk and Asriel stumbled downstairs, yawning. Giving them a quick CHECK, Sans noticed Asriel's HP was still lowered slightly from Chara's attack. He handed him a piece of monster candy as they passed. Asriel quickly popped it in his mouth, restoring his HP.

"So what is everyone doing today?" Toriel asked from the stove. She was flipping pancakes, adding them to the stack next to her. "I have a meeting with the school board in an hour."

Gaster looked up from his pancakes. He wore black pants and a grey sweater with long sleeves. Glasses were somehow perched on his face. "I just need to have a chat with Sans and his friends."

The skeleton in question was busy drowning his pancakes in ketchup. "ok. let's finish breakfast first, then take it outside."

"Asriel? Frisk? Would you like to go to the park or something like that?" Asgore asked his two children. Their eyes brightened and they started shoveling their pancakes into their mouths faster.

Gaster led Sans and his friends outside onto the front lawn. He glanced at Sans expectantly.

"Guys, I know you know me as Ness, but my name has been changed. I'm Sans now." Sans looked around at Paula, Jeff and Poo. "Sorry if that's been bothering you, but it has."

Gaster put a hand on Sans' shoulder. "He made this decision when he first came to Snowdin. It's been many long years and even more if you count the time that went past each time there was a reset or a save." The taller skeleton then smirked. "I feel like this is getting dreary. How about a little test?"

Jeff brightened, while his friends sagged. Sans also grinned. "Oh, I've missed those!"

Gaster chuckled. "Sans, Jeff, Paula, Poo, Asriel, you can all come. I know Sans will definitely want to." He grinned. "It's a fighting test."

Poo and Paula immediately wanted to go. Jeff wanted to stay and talk with Dr. Alphys. He disappeared back inside.

Gaster teleported them outside Alphys' old lab in the Underground, where the Core was. He stepped to the door and held his hands out. His left eye glowed blue and his right eye orange. The doors suddenly shimmered and shifted, becoming dark black outlined with bones. "Welcome to my lab," Gaster said, and Sans rubbed his hands together gleefully.

The smaller skeleton began running around, peering at strange machines and random objects that littered shelves in the huge room. His left eye socket flared blue with excitement, and he grinned widely.

"So where's this fighting test?" Poo asked impatiently.

Gaster moved his hand over a pad near the door, and typed in a seemingly complicated code. The room groaned as metal scraped against metal, and everything was pushed out of the way as it changed. It became a huge arena with a reinforced window on one wall. Gaster snapped his fingers and Poo and Paula were teleported into that reinforced room, as Gaster began typing things into the computer next to them. Sans teleported to one side of the arena and stood still. Gaster leaned forward and flicked a switch.

A hologram, shaped just like Chara, appeared on the opposite side of the arena from Sans. His eye suddenly brightened, a blue and gold flame shooting from it and fading.

The Chara hologram attacked Sans with vicious swipes. Holographic knives were thrown, deadly strikes gleaming within each. Sans barely took a step to either side to dodge any of them, then his hand blazed blue with a blue aura.

The Chara hologram's holographic soul turned blue, and it looked down in shock. Sans shot his right hand in the air, the Chara hologram being dragged ink the air by its soul. He stood with his left hand in his jacket pocket, slippered feet in a relaxed stance. As he snapped his hand or fingers from side to side or up or down, the Chara hologram was slammed into the corresponding wall, loosing health each time it hit.

Sans threw it against the far wall and let the Chara hologram's soul return to its dulled red. It stood and attacked even quicker. He still dodged them pretty easily.

The Chara hologram hissed.

Sans and the Chara hologram continued swapping attacks; Sans' ranging from the blue heart to bones stabbing from walls and the floor; and the Chara hologram's being holographic knives and red attacks.

Sans chipped away at the Chara hologram's health, until it finally growled and attacked yet again with huge red blade attacks.

Sans disappeared from the arena just as the holographic attacks were about to hit him and reappeared in the air a few feet away from Chara hologram and yet a hundred higher. It looked up in confusion. Sans' eye flashed and a single bone bulleted up from the ground at Chara hologram's feet, stabbing through its chest and shooting it up into the air in front of Sans.

His eye blazed with blue and gold flame, and he threw his hand up.

Gaster blasters materialized around Chara hologram in a circle, and more appeared in a column around it, dozens total.

Sans snapped his raised fingers and the Gaster blasters fired.

When the smoke cleared, Sans was standing at the edge of a massive crater, almost as large as the arena itself. He was calmly facing the reinforced room with his hands in his pockets. The Chara hologram's shattered holographic soul disappeared inside the crater.

Sans grinned. "Not my best, but I haven't practiced in a while."

Gaster laughed at both Poo's shocked expression and Paula's terrified one. "Sans, that was great."

Sans teleported inside the reinforced room. "Your turn, Poo."

Poo swallowed. "Um.. few questions? One, WHY DIDN'T YOU DO THAT AGAINST GYGIAS?! Two, the arena's kinda destroyed, and three, WHAT."

Gaster flipped the first switch down and adjusted a knob next to it. Then he pressed a button and the arena reassembled itself. "That takes care of question two. And for the other two, Sans can answer."

Sans chuckled. "I would have but I couldn't before. The Undertale Timeline activated my powers when I came here and destroyed most of my old ones. This is just what I can do."

Poo ended up failing against a hologram Chara on the easiest setting and Paula only lasted a minute more than Poo on the same setting.

 **A/N: This took a bit longer to edit, since I sort of mashed two chapters together.**

 **Hope you guys enjoyed! Sorry if I spelled Gygias wrong.**


	7. Chapter 7

**A/N: I AM ALIVE!**

 **So the past week or so has been a pain in the butt for me since the entire area was hit with a windstorm last week and it knocked out the power and lots of people are currently without electricity or any sort of thing like that. THANKS A FREAKING LOT MOTHER NATURE! Then once everything's is starting to get back on track, we get hit with a snowstorm that started Monday night and isn't that bad, just a huge pain. It's starting to melt, but that was annoying. But I've been watching/reading/listening to YouTube, FF and music. I will not venture into the Outernet. (Aka the non-internet world)**

 **But I got a bit of work done on this fic! Took me so long because every angle I tried just didn't seem right and I'm not going to post a chapter unless I think it's good.**

 **I've been working on drawing a bunch of characters while I listen to Ink and Dance!Sans' Megalovania themes on loop for about fifteen total hours this past week. So that's given me some inspiration!**

 **I also finished MatPat/GameTheory's three part video on Undertale. I want to say that as much as I love the theories, it makes me sad to see that so many people hated on his previous Undertale theories. Guys, everyone is a human being. No one is perfect. And guess what?! THOSE ARE THEORIES! Just like fanfictions, they aren't considered canon to the actual main topic unless specifically recognized by the creator of the topic and said to be canon. That's why they're called FAN-fictions and THEORIES. Not set-in-stone truth. So thank you to those who, even if you might not like the Sans=Ness theory, read on! You guys are the best!**

 **Thank you guys so much for favoriting and following! Your reviews are awesome too!**

 **NOTE: Frisk is non-binary. So is Chara, and they use they/them/their pronouns. Mettaton is male. If you don't like it, then leave (AFTER READING AND/OR REVIEWING FIRST!)**

 **DISCLAIMER: I DO NOT CLAIM TO OWN ANY UNDERTALE CHARACTERS OR THE GAME ITSELF! THAT BELONGS TO TOBY FOX! I DO NOT CLAIM TO OWN EARTHBOUND OR ANY PART OF THE MOTHER SERIES! THAT BELONGS TO ITS RESPECTIVE OWNERS! I ALSO DO NOT CLAIM TO KNOW THE SANS=NESS THEORY! That belongs (I think) to MatPat at GameTheory.**

 **Enjoy!**

Sans picked up his mug of coffee and plopped down at the table. Next to him, Frisk poked at their cereal.

"hey, kid. what's wrong? you look pretty tired," Sans asked.

Frisk yawned. "I don't want to go to school tomorrow."

"it's not that bad! remember, there's a bunch of nice kids from when we went for that intro thingy!"

The human child just shrugged and swallowed the last bite of their cereal. "I'm going to go find Asriel." They disappeared up the stairs, leaving Sans with his coffee.

Not five minutes later, Papyrus kicked in the door. "GOOD MORNING, BROTHER!" the enthusiastic skeleton yelled.

Sans sighed and went back for more coffee. "hey, paps."

"I HAVE DECIDED THAT TODAY YOU ARE COMING WITH ME TO RUN ERRANDS!" Papyrus declared.

Refilling his mug, Sans sighed. "bro, it's too early. i was gonna stay and help asgore and toriel with stuff. anyways, alphys still said i need to finish recovering my magic."

"BUT YOU CAN COME WITH ME AND JOIN IN MY COOKING LESSON WITH UNDYNE!" Papyrus begged. He tried his hest to make puppy eyes, or puppy eyesockets. "PLEASE, SANS?"

Defeated, the shorter skeleton finally agreed. "just gimmie five minutes." He trudged upstairs, shrugged on his classic blue jacket, and drained his coffee.

_time_skip_

Sans followed Papyrus to Undyne's house, his younger brother knocking sharply on the door.

"Papyrus! And Sans?! Wow!" Undyne cried, yanking open the door. "Everything's ready!" She led them inside.

Sans stared warily at the pot that sat on the stove and random veggies and boxes of spaghetti that were piled on the counter. He must've looked nervous, but both Undyne and Papyrus were hyped. He claimed a seat at the table and watched as Papyrus' cooking lesson began.

During the next hour, Sans prevented a total of twelve almost-disasters, including six fires, three explosions, two third-degree burns, and one stabbing of a certain skeleton. Undyne had apologized profoundly for the last accident, having missed the pot. The kitchen was an absolute mess. Finally, after Sans had dealt with the hysterical Undyne over almost hitting Papyrus, he had thrown out the remains of the failed spaghetti. Undyne offered to find a new pot, and did just that while Sans sent Papyrus on a run to go get fresh ingredients. Undyne made tea after finding a new pot,(the one food/drink she actually could make without almost lighting her house on fire) and took a seat at the table.

Papyrus returned with his arms full of ingredients. Undyne discovered an old cookbook in the back of a cupboard, which Sans promptly put to use.

Papyrus and Undyne watched as the normally lazy skeleton became a whirlwind of productivity. Ingredients were neatly chopped, diced, and mixed while water boiled. With perfect calm, Sans tossed the contents of no less than three boxes of spaghetti in the general direction of the stove. Undyne and Papyrus were shocked to see that that Sans had gotten all of it in the pot, and that not a single bit of spaghetti had fallen out. Once the spaghetti was cooking, Sans slapped a saucepan onto the stove and put the prepared ingredients into it. Less than ten minutes later, sauce was bubbling while spaghetti was draining in the sink. Another few minutes, and Sans set the two bowls on the table. Steam rose from both dishes.

Undyne and Papyrus stared at the prepared food. They tentatively took a bite and gasped as they tasted the perfect spaghetti.

"OH MY GOD, SANS!" Papyrus exclaimed. "THIS SPAGHETTI IS EVEN BETTER THAN MINE!"

Undyne was shoveling the pasta into her mouth as fast as she could. "It's amazing!"

Sans shrugged. He filled both pots with water and let them sit in the sink while he rummaged in Undyne's fridge. "not that hard. you guys are too aggressive. follow the recipe down to the letter and you'll be good." He discovered his target, a bottle of ketchup, and brought it to the table.

Papyrus scanned the cookbook. He blinked. "IT'S NOTHING LIKE HOW WE WERE MAKING IT!"

Undyne grabbed another heaping serving. "Look's like you should be the one giving lessons, not me!"

"like i said, it's all in the book." Sans proceeded to squirt half the contents of his ketchup bottle onto his plate of spaghetti, resulting in a lecture from Papyrus on how ketchup ruined spaghetti. Which, of course, Sans only half listened to and focused most of his attention on eating.

When everyone was full, Sans divided the leftovers into two containers. Undyne waved from the window as they started walking home.

The pair strolled along in silence for a bit, enjoying the sunlight and the noise of the surface. Then Sans' phone buzzed.

"YOU'D BETTER CHECK THAT, SANS!" Papyrus told him.

He rummaged in his pockets and found his phone. It was steadily vibrating with multiple texts and a phone call. Answering, he said, "hello?"

"SANS!" Frisk shrieked. "WE NEED YOUR HELP!"

Sans nearly tripped over his own feet and caught himself. "frisk? what's wrong?"

"Chara's back and they're attacking everyone and Mettaton's defending with Toriel but Asgore's only got ten HP left and Asriel's got a bubble around your friends and Gaster and-" Frisk sounded hysterical, freaking out.

Sans grabbed Papyrus' wrist, to the skeleton's shock, and teleported to their kitchen. Frisk jumped, dropping by their phone.

"Sans! You're here but you're still not completely recovered!" They cried.

Sans pushed them away. "go take care of asgore. papyrus, go help asriel."

The shorter skeleton stomped out onto the lawn, kicking down the front door. Quite literally, since it was weak from Papyrus earlier.

Chara, a glitched-out version, was chucking glowing red knives at Toriel. Mettaton's weird leg attack managed to knock them out of the way, but just barely. The robot was clearly running low on batteries, even with his extended charge, as he was slow and clumsy. Toriel launched more fire balls, but she was injured and her attacks didn't even do that much damage.

Sans lunged and threw up a wall of bones just as a knife slipped past Toriel's guard. "go! get inside!"

Mettaton was running on fumes, or recycled energy, and could barely stand. Quickly, Toriel helped the robot back into the house, then ran back to the porch to watch.

The glitches version of the first fallen child let out a cackle. "hELlo, SAnS! I S€E ¥Ou'Ve coMe 2 FigHT Me!" They launched a flurry of knives, which Sans dodged or blocked with a Gaster shield. Chara's voice seemed even more jerky and glitched, their words sometimes even popping up in the air beside them.

"i see you've decided to attack innocent people!" Sans retorted, summoning a Blaster and firing.

Chara danced out of the way as he fired it again and again. "Oh, n0! I tHINk ¥Ou'v€ MIssuNdERSt00D! NON€ of TheM ArE InNOC€NT! TH€Y haVE AlL KiLLEd aT 0Ne PoiNT!"

Sans thrust out his hand and trapped Chara in a cage of bones. "that doesn't matter. what matters is that you're going to die."

"ArE ¥0u ReaLL¥ ThaT Sur€?!" Chara shrieked.

A knife appeared at Sans' throat. He froze.

"If yoU KIll m€, My ATTacK WiLl DR0P Nd ¥0U wiLl DIE!" The child screamed.

Stalemate.

 **A/N: SORRY NOT SORRY!**

 **So there was a bit of happiness and a bunch of destruction for you guys!**

 **I'll keep working on all my fics, it depends if I can get a chance. I have a bunch of tests and stuff, plus championships are coming up for sports and that's important.**

 **Thank you guys so so so so so so so much for reviewing and actually reading! I can thank you guys enough but I will give you guys blue cookies! (::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::)** **(::)(::) That's about 100 blue cookies! Wait.**

 **Wrong fandom.**

 **OH WELL I DON'T GIVE A SHIT!**

 **Also I've been reading way too much Undertale, PJO, and Harry Potter fanfiction lately. I'm following and favoriting a bunch of amazing ones that you guys should totally check out if you like those fandoms!**

 **Byee!~~~~~**


	8. Author's Update

AN:

Alright, I hate authors notes as a singular chapter because they make it seem like the story is updated, but unfortunately that is not the case today.

Just letting you all know - and this AN is going up on all of my stories - I have chosen to place a haitus on all of my fics here on FFN. This is not a permanent break, nor is it a very short one. I chose to do this because I am extremely busy lately, and will be for a couple months. I also have become an active beta-reader, both on FFN and for a webcomic, and I want to make sure I have enough time to help the authors and artists that I am beta-reading for. I also went through my fics here, and have made the decision to ask you all wether or not I should continue my fics, rewrite them, or do a mix.

You can each vote on what I should do on the poll that is currently up on my profile. The poll will be open for the next couple weeks, so make sure you vote so I know what you would prefer.

The amount of readers or viewers on all of my fanfictions are awesome, and thank you all for choosing to read my writing. Like I said, my fics aren't dead, but will be updated eventually.

Thank you all, and have a lovely day.

~thederpypikachu98

TL;DR: There's a poll on my profile to see if I should rewrite stuff, I'm busy, stuff won't update for a while.


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